linux-kernel - Re: [PATCH 1/2] mtd: spi-nor: sst: register SFDP region into NVMEM framework to read MAC Address

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87eczawo9q.fsf@bootlin.com>
Date: Thu, 06 Mar 2025 09:34:41 +0100
From: Miquel Raynal <miquel.raynal@...tlin.com>
To: <Manikandan.M@...rochip.com>
Cc: <mwalle@...nel.org>,  <robh@...nel.org>,  <krzk+dt@...nel.org>,
  <conor+dt@...nel.org>,  <Nicolas.Ferre@...rochip.com>,
  <alexandre.belloni@...tlin.com>,  <claudiu.beznea@...on.dev>,
  <tudor.ambarus@...aro.org>,  <pratyush@...nel.org>,  <richard@....at>,
  <vigneshr@...com>,  <devicetree@...r.kernel.org>,
  <linux-arm-kernel@...ts.infradead.org>,  <linux-kernel@...r.kernel.org>,
  <linux-mtd@...ts.infradead.org>,  <Varshini.Rajendran@...rochip.com>
Subject: Re: [PATCH 1/2] mtd: spi-nor: sst: register SFDP region into NVMEM
 framework to read MAC Address


>>> +static int sst26vf_nor_post_sfdp(struct spi_nor *nor)
>>> +{
>>> +     struct nvmem_device *nvmem;
>>> +
>>> +     sst26vf_sfdp_nvmem_config.dev = nor->dev;
>>> +     sst26vf_sfdp_nvmem_config.size = nor->sfdp->num_dwords * sizeof(*nor->sfdp->dwords);
>>> +     sst26vf_sfdp_nvmem_config.priv = nor;
>>> +     sst26vf_sfdp_nvmem_config.reg_read = sst26vf_sfdp_mac_addr_read;
>>> +
>>> +     nvmem = devm_nvmem_register(nor->dev, &sst26vf_sfdp_nvmem_config);
>>> +     if (IS_ERR(nvmem)) {
>>> +             dev_err(nor->dev, "failed to register NVMEM device: %ld\n", PTR_ERR(nvmem));
>>> +             return PTR_ERR(nvmem);
>> 
>> I don't think it makes sense to have this one-off in a particular
>> driver. If at all, this should be handled in the core. Sorry, but
>> this really looks like an ugly hack.
>> 
>
> Because the EUI identifier within the SFDP is unique to the 
> SST26VF064BEUI flash, I opted to handle it here rather than in the core.
>
> Also here the MAC address data resides within the 0x260-0x26F range, I 
> will resize the nvmem_config.size to 0x10 instead of registering the 
> full SFDP region as NVMEM.

Open question to all parties in this thread: how do we give an offset in
the device tree that is relative to the sfdp region and not the data
region? I believe we care not to mix these areas while describing.

Thanks,
Miquèl